Search Publications
Unequivocal detection of the tidal deformation of a red giant in a binary system via interferometry
Boffin, Henri M. J.; Merc, Jaroslav
While mass transfer in binary systems is a crucial aspect of binary evolution models, it remains far from understood. HD 352 is a spectroscopic binary exhibiting ellipsoidal variability, likely due to a tidally deformed giant donor filling its Roche lobe and transferring matter to a faint companion. Here, we analyze VLTI/PIONIER interferometric ob…
Discovery of three magnetic helium-rich hot subdwarfs with SALT
Dorsch, M.; Jeffery, C. S.; Woolf, V. M. +6 more
Magnetic fields with strengths ranging from 300 to 500 kG have recently been discovered in a group of four extremely similar helium-rich hot subdwarf (He-sdO) stars. In addition to their strong magnetic fields, these He-sdO stars are characterised by common atmospheric parameters, clustering around Teff = 46 500 K, a log ɡ/cm s‑1
Origin of the Chromospheric Umbral Waves in Sunspots
Xu, Zhe; Xue, Zhike; Yan, Xiaoli +5 more
Oscillations are ubiquitous in sunspots and the associated higher atmospheres. However, it is still unclear whether these oscillations are driven by the external acoustic waves (p-modes) or generated by the internal magnetoconvection. To obtain clues about the driving source of umbral waves in sunspots, we analyzed the spiral wave patterns (SWPs) …
Enhancing Exoplanet Ephemerides by Leveraging Professional and Citizen Science Data: A Test Case with WASP-77 A b
Dalba, Paul A.; Zellem, Robert T.; Evans, Phil +42 more
We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telesc…
Linear polarization study of open clusters in the anticenter direction: Signature of the spiral arms
Ganesh, Shashikiran; Joshi, Santosh; Uppal, Namita +2 more
Aims. Our objective is to investigate the distribution of dust and associated large-scale structures of the Galaxy using optical linear polarization measurements of various open clusters located at different distances in the Galactic anticenter direction. Methods. We present R-band linear polarization observations of stars toward five open cluster…
Tidal Disruption Event AT2020ocn: Early Time X-Ray Flares Caused by a Possible Disk Alignment Process
Jonker, P. G.; Zabludoff, A. I.; Pasham, D. R. +3 more
A tidal disruption event (TDE) may occur when a star is torn apart by the tidal force of a black hole (BH). Eventually, an accretion disk is thought to form out of stellar debris falling back toward the BH. If the star's orbital angular momentum vector prior to disruption is not aligned with the BH spin angular momentum vector, the disk will be ti…
Concurrent kink and sausage waves in a crescent-shaped structure over a limb prominence
Ghiasi, Maryam; Dadashi, Neda; Ebadi, Hossein
A Crescent-shaped prominence Structure (CS) over the solar west limb is studied using Extreme Ultra-Violet (EUV) Imaging Spectrometer/Hinode and Atmospheric Imaging Assembly (AIA)/Solar Dynamics Observatory (SDO). First, the time-varying positions of the top and bottom borders of the CS, along with its central axis, are derived. Time evolutions of…
Ups and downs in the X-ray emission of the colliding wind binaries HD 168112 and HD 167971
Blomme, R.; Nazé, Y.; Rauw, G. +2 more
Context. The long-period O-star binary system HD 168112 and the triple O-star system HD 167971 are well-known sources of non-thermal radio emission that arises from a colliding wind interaction. The wind-wind collisions in these systems should result in phase-dependent X-ray emissions. The presence of a population of relativistic electrons in the …
Mutual occurrence ratio of planets - I. New clues to reveal origins of hot and warm Jupiter from the RV sample
Zhang, Hui; Zhou, Ji-Lin; Su, Xiang-Ning
Many studies have analysed planetary occurrence rates and their dependence on the host's properties to provide clues to planet formation, but few have focused on the mutual occurrence ratio of different kinds of planets. Such relations reveal whether and how one type of planet evolves into another, e.g. from a cold Jupiter (CJ) to a warm Jupiter (…
The ESO-VLT MIKiS survey reloaded: The internal kinematics of the core of M75
Vesperini, Enrico; Cadelano, Mario; Pallanca, Cristina +7 more
We present the results of a study aimed at characterizing the kinematics of the inner regions of the halo globular cluster M75 (NGC 6864) based on data acquired as part of the ESO-VLT Multi-Instrument Kinematic Survey (MIKiS) of Galactic globular clusters. Our analysis includes the first determination of the line-of-sight velocity dispersion profi…